My condolences on your husband's passing.If the serial# is on the headstock decal, below the word "fender", the bass is very likely a 1977 Precision. The badassII bridge is an aftermarketadd on that can improve the bass' sound. If the original parts can be found, theywill add to the instrument's value.

Fender.com may be a good source for information. You can also try some stores. The folks at basspalace.com are friendly, well informed and ethical business people.

If you are considering selling, be forewarned. many will try to offer you nominal amounts of cash for the instrument,claiming its old...etc. Market prices for instruments of this vintage in excellent condition are hovering at about $800. A reasonableretailer will offer you $400-500(they need to make a living). Don't sell it for anythingless. You would be best served to sell it on eBay, where the macho bidding frenzyusually results in these things selling for more than they are worth.